AIM: To assess the protective effect of human umbilical cord mesenchymal stem cell exosomes (hucMSC-Exs) in a diabetic rat model by using a variety of retinal bioassays. METHODS: hucMSCs were subjected to differential ultracentrifugation for the collection of exosomes, and transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) using a NanoSight analysis system and Western blotting (WB) were used to analyze the expression of surface marker proteins such as CD63, CD9 and Calnexin. Streptozotocin (STZ) was injected into the intraperitoneal cavity to establish a diabetic model. Rats were divided into a normal group, diabetic group and hucMSC-Ex group. Fundus fluorescein angiography (FFA), optical coherence tomography (OCT) and other live imaging methods were used to observe the fundus of the rats. Finally, the eyeballs of rats from each group were collected for hematoxylin-eosin (HE) staining to further analyze the retinal structure. RESULTS: Through TEM, NTA and WB, we successfully isolated hucMSC-Exs. Subsequent FFA and OCT confirmed that hucMSC-Exs effectively prevented early retinal vascular damage and thickening of the retina. Finally, HE staining of rat retinal sections revealed that exosomes effectively alleviated retinal structure disruption caused by diabetes. CONCLUSION: hucMSC-Exs have a protective effect on the retina in diabetic rat through FFA, OCT and HE staining.

中文翻译：

---

通过活体视网膜成像观察脐带间充质干细胞外泌体对糖尿病大鼠模型的保护作用

目的：通过使用多种视网膜生物测定法评估人脐带间充质干细胞外泌体（hucMSC-Exs）对糖尿病大鼠模型的保护作用。方法：对hucMSCs进行差速超速离心以收集外泌体，并使用透射电子显微镜（TEM）、使用NanoSight分析系统的纳米颗粒跟踪分析（NTA）和蛋白质印迹（WB）来分析表面标记蛋白的表达，例如如 CD63、CD9 和钙联蛋白。腹腔注射链脲佐菌素（STZ）建立糖尿病模型。将大鼠分为正常组、糖尿病组和hucMSC-Ex组。采用荧光素眼底血管造影（FFA）、光学相干断层扫描（OCT）等活体成像方法观察大鼠眼底。最后，采集各组大鼠眼球进行苏木精-伊红（HE）染色，进一步分析视网膜结构。结果：通过TEM、NTA和WB，我们成功分离了hucMSC-Ex。随后的FFA和OCT证实hucMSC-Exs有效预防早期视网膜血管损伤和视网膜增厚。最后，大鼠视网膜切片的HE染色显示，外泌体有效减轻了糖尿病引起的视网膜结构破坏。结论：通过FFA、OCT和HE染色显示hucMSC-Exs对糖尿病大鼠视网膜具有保护作用。